1. Field of the Invention
The present invention relates to a fabric window blind and more particularly, to a double-layer fabric roller blind.
2. Description of the Related Art
FIGS. 1 and 2 show a conventional roller blind. This structure of roller blind 1 comprises a cylindrical roller 2 horizontally affixed to the top side of a window and rotatable manually or by means of electric driving means, a bottom rail 3 spaced below the roller 2, a plurality of soft slats 4 arranged in parallel at different elevations between the roller 2 and the bottom rail 3, each soft slat 4 having two opposite long sides respectively hemmed with a support rod 5, two cord member sets 6 arranged in parallel near two lateral sides, each cord member set 6 having a front cord 7 and a rear cord 8 respectively connected between the roller 2 and the bottom rail 3 and joined to the two opposite long sides of each slat 4, and two shades 9 respectively vertically arranged at the front and back sides of the roller blind 1 and respectively connected between the roller 2 and the bottom rail 3. The shades 9 have a proper light transmittance (for example, made of gauze cloth). The size of the shades 9 is approximately equal to the size of the window.
By means of the aforesaid arrangement, the slats 9 are covered over the front and back side of the shades 4 to filter light and to decorate the roller blind 1. After the roller blind 1 has been fully extended out, the user can rotate the roller 2 to move the front cord 7 and rear cord 8 of each cord member set 6 in reversed directions to further tilt the slats 4. Further, when continuously rotate the roller 2 forwards or backwards, the roller 2 is forced to roll up the slats 4 with the support rods 5 and the shades 9, as shown in FIG. 2, and therefore the roller blind can be received to the top side of the window, and positioned in the desired elevational position to block a part of the window.
The aforesaid roller blind 1 is still not satisfactory in function. When rotating the roller 2 to receive the slats 4 with the support rods 5 and the cord member sets 6 as well as the shades 9 to the periphery of the roller 2, the rolled-up size is greatly increased. In order to receive the rolled-up structure of the roller 2, slats 4, support rods 5, cord member sets 6 and shades 9, the size (transverse width of the head frame) must be relatively increased. Installing a bulky head frame in the top side of a window destroy the sense of beauty of the window. When rotating the roller 2 to roll up the slats 4 with the support rods 5, the cord member sets 6 and the shades 9, the shades 9 are wrapped on the support rods 5 and the cord member sets 6 and caused to wrinkle. Further, because the cord member sets are fastened to the roller 2, the user can rotate the roller 2 to tilt the slats 4 only when the roller blind 1 has been fully extended out. If the roller blind 1 is rolled up to a desire elevation, i.e. the slats 4 are received in a vertical position between the shades 9, the user cannot adjust the tilting angle of the received slats 4.